Knife holder in log slabbing chipper

ABSTRACT

The chipper comprises a rotor with a plurality of knives adapted to slab off the side of a log so that the first saw cut following the chipper removes a usable board. In order to make usable pulp chips, the chipper knives are of bent configuration, each having a grain cutting portion which cuts across the grain and a planing portion which cuts parallel with the grain to leave a smooth board surface on the log as it is moved lengthwise past the chipper on a saw carriage. Each knife is clamped rigidly in working position by a clamp plate which is tightened on a pair of wedges adjacent the side edges of the knife. The clamp plate is crowned, causing it to flatten against substantially the whole area of the knife when the clamp plate is tightened on the wedges.

[ Dec. 11, 1973 1 KNIFE HOLDER IN LOG SLABBING CHIPPER [75] Inventor:Frederick L. B. Miller, Lake Oswego, Oreg.

[73] Assignee: Chipper Machines and Engineering Corporation, LakeOswego, Oreg.

Filed: May 11, 1972 Appl. No.: 252,230

[56] References Cited UNITED STATES PATENTS 11/1892 Quinn 144/22511/1966 Standall.. 144/220 3/l97l Hickman 144/220 PrimaryExaminer-Donald R. Schran Attorney-Lee R. Schermerhorn [57] ABSTRACT Thechipper comprises a rotor with a plurality of knives adapted to slab offthe side of a log so that the first saw cut following the chipperremoves a usable board. In order to make usable pulp chips, the chipperknives are of bent configuration, each having a grain cutting portionwhich cuts across the grain and a planing portion which cuts parallelwith the grain to leave a smooth board surface on the log as it is movedlengthwise past the chipper on a saw carriage. Each knife is clampedrigidly in working position by a clamp plate which is tightened on apair of wedges adjacent the side edges of the knife. The clamp plate iscrowned, causing it to flatten against substantially the whole area ofthe knife when the clamp plate is tightened on the wedges.

9 Claims, 16 Drawing Figures PATENTED DEC 1 I973 sum 1 or 4 PAIENTED DEC1 1 I975 SHEET 2 0F 4 1 KNIFE HOLDER IN LOG SLABBING CHIPPER BACKGROUNDOF THE INVENTION This invention relates to an improved knife holder in awoodworking machine such as, but not limited to, a log slabbing chipperor edger.

In conventional practice, chipper knives are secured in the rotor headby clamp plates secured by screws perpendicular to the knife blade. Thismounting arrangement requires deep slots in the knives to receive theclamp screws since the position of the knife varies in relation to theclamp screws as the knife becomes narrower from repeated sharpening. Theslots complicate the manufacture of the knives, reduce the strength ofthe knives, introduce undesirable stresses in heat treating and reducethe service life of the knives by limiting the number of times theymaybe re-sharpened.

Also, the conventional knife clamping arrangements require a high degreeof dimensional accuracy for positive positioning of the interfittingparts and provide'inadequate support for the knife, resulting infrequent breakage. These deficiencies also often result in damage to theknife holder as well as the knife, thereby further increasing themaintenance cost of the machine.

Objects of the invention are, therefore, to provide an improved knifeholder in a log slabbing chipper, to provide a knife holder whichprovides better support for the knife, to provide a knife holder whichreduces breakage of both knives and holders, to provide a knife holderwhich will increase the service life of the knife and to provide a knifeholder adapted to receive unslotted knives.

SUMMARY OF THE INVENTION A primary feature of the present invention isthe use of unslotted knives. Crowned and tapered clamp plates areflattened against a face of the knife as the clamp plates are tightenedon wedges extending along the side edges of the knife. This providesmore rigid support for the knife, reducing knife and holder breakage,allows the use of stronger knives which are less complicated tomanufacture and, at the same time, allows greater dimensional tolerancesto the parts since the angular seat in the knife holder serves toposition the knife along with the backing bar assembly.

The invention will be better understood and additional objects andadvantages will become apparent from the following description of thepreferred embodiments illustrated in the accompanying drawings. Variouschanges may be made, however, in details of construction and arrangementof parts and certain features may be used without others. All suchmodifications within the scope of the appended claims are included inthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic top plan viewillustrating the function of a log slabbing chipper;

FIG. 2 is a view on the line 2-2 in FIG. 1, with parts broken away;

FIG. 3 is a perspective view of the chipper; FIG. 4 is a perspectiveview of a knife holder in FIG. 3;

FIG. 5 is a back end view of the knife clamp plate showing the crown;

FIG. 6 is a perspective view of a knife;

FIG. 7, 8 and 9 are fragmentary plan views of a knife showing the extentto which it may be re-sharpened for use in the present machine;

FIG. 10 is a view showing the present knife holder mounted on a chipperrotor head;

FIG. 11 is an elevation view of the knife holder;

FIG. 12 is a view on the line 12-12 in FIG. 11;

FIG. 13 is a view on the line l313 in FIG. 11;

FIG. 14 is a view on the line 14--l4 in FIG. 11;

FIG. 15 is a perspective view of a modified rotor head embodying theinvention; and

FIG. 16 is a view on the line 16-16 in FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a top plan viewillustrating diagrammatically the function of chipper machine 10 inslabbing off one side of a log L preparatory for the first cut ofvertical band saw S. The log is mounted on carriage 11 for iongitudinaltravel in the direction of arrow 12. FIG. 2 shows the position of thelog and carriage before they have been shifted over to chipper 10 forthe desired depth of cut as represented by the broken line 15'. Whenthis adjustment has been made and the carriage and log are traversedpast the chipper, the chipper planes off the flat vertical surface 15 inFIG. 1, producing usable pulp chips of relatively high value. Beforechippers were developed for this purpose, the surface 15 was cut by afirst pass of the log through band saw S resulting in sawdust of arelatively low value and a slab of no value until reduced to chips in asubsequent operation.

Band saw S rotates over an upper pulley 16 so as to made a downwardvertical saw cut 17 in the log. Chipper 10 is adjusted relative tothevertical plane of the saw so as to produce the desired thickness ofboard B. Thus, in cutting the first board B, the only waste material oflow value is the sawdust from the kerf of saw cut 17. The first saw cutmakes a usable board having one side planed.

Chipper machine 10 comprises a base frame 20 rigidly secured to a flooror heavy foundation by bolts 21 in FIG. 3. The frame 22 of the chippermachine is mounted for sliding movement on base 20 and is adjustabletoward and away from the vertical cutting plane of the saw by hydrauliccylinders 23 and piston rods 24 connected between base 20 and frame 22on opposite sides of the machine.

Mounted on the movable frame 22 is a rotor head 25 rotatable on ahorizontal axis and driven in the direction of arrow 26 by driven pulley27. Pulley 27 is belted to a motor in the casing 22. Mounted on rotorhead 25 is a plurality of knife holders 30 which incorporate importantfeatures of the present invention.

Each knife holder 30 carries a knife 35 which will be described withreference to FIGS. 6 to 9 and 13. The knife 35 comprises a bent bladehaving a sharpened planing edge portion 36 and a sharpened chip cuttingedge portion 37. The planing edge portion 36 planes the smooth, flatsurface 15 on the log in FIG. 1 while the chip cutting edge portion 37cuts off chips on a con- The rear edge 42 of shank portion 41 isprovided with a plurality of keyhole slots 43. These slots are chamferedon one side as indicated at 44 in FIG. 7. FIG. 7 is a fragmentary planview of shank portion 41.

Referring now to FIG. 8, Babbitt material 46 is cast on back edge 42 andinterlocked in the chamfered keyhole slots 43. This provides a constantwidth W which is maintained throughout the life of the knife. Each timethe cutting edge 36, 37 is sharpened, the Babbitt material 46 is removedand the knife is placed in a jig for casting a new layer of the Babbittmaterial 46. After repeated sharpenings the knife becomes narrower andthe Babbitt material 46 increases in width to maintain the constantdimension W as shown in FIG. 9. This allows the knife to be re-sharpenedmany times before it is too narrow for further use since there are nodeep slots to receive the usual clamp screws.

Referring now to FIG. 13, a keeper bar 45 is provided with tapped holesto receive screws 49 which secure a backing bar 50 to the keeper bar.For purposes of fine adjustment, shims 51 are interposed between backingbar 50 and keeper bar 45. This is a permanent adjustment which is notchanged when the knives are sharpened. Backing bar 50 is provided with alocating flange 52. These parts form a backing bar assembly which willbe referred to again after describing the knife holders 30.

As seen in FIG. 4, each holder 30 has a flat base portion 55 with holes56 to receive screws for mounting the holder on a flat side 57 of therotor head 25. The mounting surface 57 appears in FIG. 3. In the presentillustration the rotor is octagonal with eight side surfaces 57 eachlying in a plane parallel with the rotor axis and each carrying one ofthe knife holders 30. Thus, the eight flat surfaces 57 are allperpendicular to the rotor end surface 58 in FIG. 3.

Referring now to FIG. 11, each knife holder 30 has a short straight leg60 perpendicular to base 55 and a long straight leg 61 disposed at anangle of approximately l25 to leg 60. The outer end of leg 61 issupported by a curved back leg 62, the parts 55, 60, 61 and 62 formingan integral one-piece casting having a chip opening 63 extendingtherethrough.

Leg portions 60 and 61 of the holder 30 have fiat inside supportingsurfaces 65 and 66 to receive and position the back sides of the knifeshank portions 40 and 41 as shown in FIGS. 12, 13 and 14. Opposed to thesupporting surface 66 at the outer end thereof is a flat abutmentsurface 67 on the leg 61. In a similar manner, base portion 55 isprovided with an abutment surface 68 opposed to the knife supportingsurface 65. A wedge 70 is welded to abutment 68 and a wedge 71 is weldedto abutment 67. These wedge elements may be formed integral with theholder casting 30, if desired. The two exposed wedge surfaces 72 and 73are disposed in parallel planes.

The knife clamp plate 75 in FIG. has a wedging surface 76 on one side toslide on the wedge 70 and a wedging surface 77 on its other side toslide on the wedge 71. Surfaces 76 and 77 are disposed in parallelplanes. This sliding movement is produced by a single screw adjustmentas shown in FIG. 13. The rearward end of clamp plate 75 contains atapped hole 78 extending parallel with the knife. A screw 80 is securedin hole 78 and projects through a slot 81 in an ear 82 on the rearwardside of leg 61 of holder 30 relative to the direction of rotation of therotor. Clamp plate 75 is pulled to the right in FIGS. 12 to 14 by meansof a nut 83 on the screw which bears against the rearward side of car82, the nut having a groove 84 which enters slot 81. The nut isturned'clockwise to tighten the clamp plate and counterclockwise toloosen it.

Clamp plate 75 is crowned in a transverse arch as indicated by the smallangles 85 in FIG. 5. This causes the convex surface 86 of the clampplate to bear first against the mid portion of knife 35. Then as theclamp plate is pulled rearward by the tightening of nut 83, the sidewedges 70 and 71 flatten the clamp plate, which is resilient, removingthe crown and causing surface 86 to bear against substantially theentire surface of shank portion 41 of the knife. At the same time, anangled surface 87 extending along one side of the clamp plate bearsagainst the shank portion 41 of the knife, clamping it firmly againstsupporting surface 65. The angular knife seat 65, 66 serves aspositioning means for the knife. This dual clamping action against shankportions 40 and 41 allows the use of two-piece knives, if desired,whereby the shank portion 40 may be a separate knife.

In the above described clamping operation the projection of the knifefrom the holder is fixed by flange 52 on backing bar 50 which projectsinto slot 90 in leg 61 of the holder as shown in FIG. 13. Screws 91enter tapped holes in knife backing bar 50 to secure the backing barassembly in the holder.

In operation, the log approaches the machine from the left in FIG. 3 andtravels to the right so that the cutting strokes of the knives are in adownward direction. The chips pass through openings 63 in the knifeholders and, for the most part, are impelled downward into a chip bin orconveyor in the base of the machine. A hood 94 covers the upper portionof the rotor to prevent the upward discharge of stray chips.

In FIG. 3 the end surface 58 of the rotor comprises a smooth, flat, orslightly crowned, plate to bear against and guide the planed surface 15of the log as it is carried past the chipper by carriage 11. In FIG. 10the effective plane of this bearing surface is represented by the brokenline 96. By means of the shims 51 in FIG. 13, the edges 36 of the knivesare adjusted to cut in a plane a very slight distance in an axialdirection from the plane 96 to provide a slight clearance space.

The present clamping arrangement employing wedge action on a crownedclamp plate is also obviously readily adaptable to a single flat knife.The invention as thus far described is not limited to chippers.

FIGS. 15 and 16 show a modification wherein the chipping head or rotorhas integral knife holders. The rotor 100 has a smooth log-supportingand guiding end surface 101 corresponding to the end surface 58 in FIG.3. The back end of the rotor has a cylindrical portion 102.

Extending between the end portions 101 and 102 is a series of flat plateportions 103, each of which recedes radially at its trailing end toprovide an opening at 104 for the passage of chips into the inside ofthe rotor. Knives 35 are the same as shown in FIGS. 6 to 9 havingsharpened planing edges 36 and sharpened chip cutting edges 37. On theinside of each plate portion 103 is a supporting surface 66 for knifeshank portion 41 and a supporting surface 65 for knife shank portionWedges 70 and 71 are mounted on abutment surfaces 68 and 67. Crowned,resilient clamp plate 75 has slide surfaces 76 and 77 along its sideedges engaging the respective wedges. The clamp plate tighteningmechanism in FIG. 13 is accessible inside the rotor to tighten the clampplates against the knives, as described in the first embodiment. Theoperation of the machine is the same as described in connection with thefirst embodiment.

Having now described my invention and in what manner the same may beused, what I claim as new and desire to protect by Letters Patent is:

l. A holding means for a woodworking knife comprising a support memberhaving a surface arranged to support one face of the knife, a pair ofwedging abutment surfaces opposed to said knife supporting surface alongopposite sides thereof, a resilient, crowned clamp plate having a pairof wedge surfaces extending along opposite sides thereof on a back faceof the clamp plate for sliding engagement with said wedging abutmentsurfaces, the crown portion of said clamp plate being arched betweensaid wedge surfaces to engage a mid portion of the oppsite face of theknife, means to slide said clamp plate on said wedging abutment surfacescausing the arch of said clamp plate to flatten against and clampsubstantially the whole area of said knife against said supportingsurface, and means to hold the knife against said sliding movement.

2. A holding means as defined in claim 1, said wedge surfaces beinginclined in a direction to flatten said clamp plate when said clampplate is moved away from the cutting edge of the knife.

3. A holding means as defined in claim 2, said sliding means comprisinga single screw on the back edge of said clamp plate.

4. A holding means as defined in claim 1, said support member having twoknife supporting portions disposed in angular relation to each other,one of said wedging abutment surfaces being opposed to one ofsaidsupporting surface portions and the other wedging abutment surfacebeing opposed to the other supporting surface portion, said clamp platehaving knife engaging surfaces opposed to both of said supportingsurface portions.

5. A holding means as defined in claim 4 including a rotor having kniveseach with a planing portion and chip cutting portion, one of saidsupporting surface portions supporting said planing portion of a knifeand the other supporting surface portion said chip cutting portion.

6. A holding means as defined in claim 1, said means to hold said knifeagainst sliding movement comprising a flanged backing bar assembly, anda groove in said support member arranged to receive said flange.

7. A holding means as defined in claim 1, said holding means being openon the back side of said clamp plate for the passage of chips.

8. A holding means as defined in claim 1 including a rotor, said supportmember comprising an integral structural part of said rotor.

9. A holding means as defined'in claim 8, said rotor being generallyfrusto-conical in shape with a circumferential series of wall memberswhich recede radially toward their trailing ends to provide a chipopening between the trailing end of each wall member and the leading endof the following wall member, and the inside of each of said wallmembers containing said knife supporting surface.

1. A holding means for a woodworking knife comprising a support member having a surface arranged to support one face of the knife, a pair of wedging abutment surfaces opposed to said knife supporting surface along opposite sides thereof, a resilient, crowned clamp plate having a pair of wedge surfaces extending along opposite sides thereof on a back face of the clamp plate for sliding engagement with said wedging abutment surfaces, the crown portion of said clamp plate being arched between said wedge surfaces to engage a mid portion of the oppsite face of the knife, means to slide said clamp plate on said wedging abutment surfaces causing the arch of said clamp plate to flatten against and clamp substantially the whole area of said knife against said supporting surface, and means to hold the knife against said slIding movement.
 2. A holding means as defined in claim 1, said wedge surfaces being inclined in a direction to flatten said clamp plate when said clamp plate is moved away from the cutting edge of the knife.
 3. A holding means as defined in claim 2, said sliding means comprising a single screw on the back edge of said clamp plate.
 4. A holding means as defined in claim 1, said support member having two knife supporting portions disposed in angular relation to each other, one of said wedging abutment surfaces being opposed to one of said supporting surface portions and the other wedging abutment surface being opposed to the other supporting surface portion, said clamp plate having knife engaging surfaces opposed to both of said supporting surface portions.
 5. A holding means as defined in claim 4 including a rotor having knives each with a planing portion and chip cutting portion, one of said supporting surface portions supporting said planing portion of a knife and the other supporting surface portion said chip cutting portion.
 6. A holding means as defined in claim 1, said means to hold said knife against sliding movement comprising a flanged backing bar assembly, and a groove in said support member arranged to receive said flange.
 7. A holding means as defined in claim 1, said holding means being open on the back side of said clamp plate for the passage of chips.
 8. A holding means as defined in claim 1 including a rotor, said support member comprising an integral structural part of said rotor.
 9. A holding means as defined in claim 8, said rotor being generally frusto-conical in shape with a circumferential series of wall members which recede radially toward their trailing ends to provide a chip opening between the trailing end of each wall member and the leading end of the following wall member, and the inside of each of said wall members containing said knife supporting surface. 